Radios:
All the top brands (Futaba, JR, Multiplex, ...) produce good stuff. It is good if you can find local support for your brand, at least in the form of other flyers who use the same brand.

Not sure but I think buddy box systems might not work between all the different brands.

Oh, I am using a JR radio and am not going to argue with anyone using something different.

edit:
Simulator practice might be useful.
FMS, or something that you have to pay for.